Electromechanical cylinder lock

ABSTRACT

An electromechanical cylinder lock includes an outer lock shell and a rotatable lock barrel located therein which is controlled by dual locking features. A side bar or fence selectively blocks and permits rotation of the barrel with respect to the shell in response to insertion of a key into a keyway in the barrel. A slider bar is movable between a blocking position in which the side bar is prevented from permitting rotation of the barrel, and an unblocking position in which the side bar permits rotation of the barrel. Alternately, a blocking mechanism is provided to block motion of tumbler pins in the cylinder lock. A shape memory alloy actuator, such as a wire made of nitinol, disposed in the barrel is activated by an electric current in response to determination by an electronic control device whether an attempt to open the lock is authorized. Thermal interlock protection from external heating of the lock is also provided.

CROSS REFERENCE TO RELATED APPLICATION

This application is a continuation of U.S. patent application Ser. No.12/724,013, filed Mar. 15, 2010, which is a continuation of U.S. patentapplication Ser. No. 08/800,742, filed on Feb. 14, 1997, now U.S. Pat.No. 7,690,231, issued on Apr. 6, 2010, the entire disclosure of which isincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to an electromechanical cylinderlock and, in particular, to a cylinder lock in which an electricalactuator is employed to provide access to the lock cylinder.

2. Description of Related Art

Electromechanical locking devices are known which include electricallyinterfaced or controlled release mechanisms for operating a lockcylinder. For example, U.S. Pat. No. 4,712,398 discloses an electroniclocking system comprising a lock cylinder with a rotatable plug locatedtherein. An electronically activated release assembly is provided whichselectively disengages a locking pin from the plug to allow turning ofthe key to rotate the plug relative to the cylinder. The lock cylinderand key each include an electronic memory device containing keyingsystem codes. Upon insertion of the key the release mechanism disengagesthe locking pin from the plug to allow its rotation. U.S. Pat. No.5,552,777 discloses another type of electromechanical cylinder lockhaving a blocking pin and an electromagnetic solenoid in the cylinderplug. The blocking pin extends into a recess in the cylinder shell, andis retracted upon actuation of the solenoid by a microprocessor in thekey.

One benefit of including electronic control features in locks is theability to provide increased keying codes for operating the lock. Forexample, information can be stored in the lock and/or key such that thelocking mechanism is activated in response to detecting and/orexchanging data. As the information stored in the components may bealtered, it is possible to vary the keying codes without changing thesystem hardware. In contrast, changing the mechanical keying codes in apurely mechanical lock typically requires forming a new key withdifferent bitting surfaces, a more involved process than reprogrammingelectronic components of an electromechanical lock.

Despite progress made in the development of prior art electromechanicallocking systems, several deficiencies exist which leave room forimprovement. For example, prior art systems do not provide the abilityto retrofit a purely mechanical lock to form an electromechanical lockwhich is operated at least in part by information stored in a key and/orlock cylinder. The benefits of retrofitting a mechanical lock in thismanner include preventing the need to alter the keying of the lockshould it become necessary to change the combination, for example whenan employee loses his or her key or leaves an establishment. In such acase, the components of the lock may be reprogrammed to change thekeying codes to prevent the employee's key from operating the lock.Additionally, prior art systems using electromagnetic components such assolenoids have been found to be impractical, because of the small spaceavailable and the relatively large size of components needed to developenough force to release the blocking mechanism. Accordingly, thereremains a need in the art for an improved electromechanical cylinderlock system.

SUMMARY OF THE INVENTION

The present invention provides an electro-mechanical cylinder lockhaving at least one, and preferably dual locking features. The lockincludes an outer shell or cylinder member, a plug or barrel rotatablymounted within the shell, and a plurality of tumbler pins which arelifted to a shear line of the barrel and shell to operate the lock. Aside bar or fence member is provided and cooperates between the shelland barrel to selectively block or permit rotation of the barrel. Theside bar has an outer edge located in a recess formed in the shell andis spring biased toward the recess. In a blocked position, the side barprevents rotation of the barrel. To permit rotation of the barrel, theside bar is moved out of the cavity and toward the barrel by a cammingaction in order to permit rotation of the barrel. The side bar isprevented from being cammed by a slider bar positioned against the sidebar. When an authorized key is inserted into the lock, a controllerdevice in the lock activates an actuator mechanism to move the sliderbar to a position over a recess in the side bar, thus allowing the sidebar to be cammed into the barrel by rotation of the barrel.

The controller device, for example a microprocessor located within oroutside the barrel, has data stored therein including authorized codesfor operating the lock. The control device compares data read ordetected from the user's key with the stored data to determine whetherthe actuator mechanism should be activated to move the slider bar to anunblocking position with respect to the side bar. The lock cylinder caninclude a keyway and a plurality of tumbler pins, the keyway receiving akey which is bitted to position the pins at a shear line which permitsthe barrel to be rotated.

Alternatively, the locking mechanism may be of a type which does notutilize tumbler pins. The key is provided with means for storing data,for example, a microchip, magnetic data-encoded strip, and the like,such that upon insertion into the keyway the controller device comparesdata transmitted by the key to determine whether the attempt to operatethe lock is authorized, and if so, activates the actuator mechanism tomove the slider bar to an unblocking position.

In a preferred embodiment, the actuator mechanism includes a length ofshape memory alloy material (one example of which is nitinol wire)attached to the slider bar and electrically coupled to the controllerdevice. Shape memory alloy is a material which can be set to deform whenheated. For example, a length of nitinol wire may be formed such thatupon heating, such as by passing a small amount of current through thenitinol wire, the wire will contract, causing the slider bar to be movedto the unblocking position, allowing the side bar to be cammed byrotation of the cylinder barrel.

An important benefit of the invention resides in the fact that the sidebar, slider bar and electrically powered actuator device are entirely(or substantially entirely) contained within the barrel. This permitsthe entire barrel to be removed and placed in the outer shells ofdifferent lock cylinders. The invention permits the barrel to besubstituted for the barrel of a purely mechanical cylinder lock toretrofit the lock into an electromechanical lock system. In addition,the invention contemplates utilizing different but interchangeableelectromechanical barrels with a plurality of lock cylinders in a locksystem. Moreover, the compact, removable barrel may carry some or all ofthe electronic hardware, firmware and/or software associated with thelock to provide even greater flexibility in various applications.

According to another aspect of the present invention, a thermalinterlock mechanism is provided to prevent attempts at circumventing aheat-actuated lock release through external heating of the lock, bydisabling the lock upon such external heating.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects, features and benefits of the invention will becomeapparent from the detailed description of preferred embodiments setforth below, taken in conjunction with the accompanying drawing figures,wherein:

FIG. 1 is a rear elevation view in section of a lock cylinder includinga shell, a rotatable plug containing movable locking members, and a sidebar constructed according to one embodiment of the present invention,the movable locking members and side bar being oriented in a cylinderlocking position;

FIG. 2 is an exploded view of the side bar locking mechanism assemblyaccording to a first embodiment of the present invention;

FIGS. 3A and 3B are three dimensional views of the side bar assemblyaccording to the first embodiment of the present invention, in a lockedand unlocked position, respectively;

FIG. 4 is an exploded view of the side bar locking assembly according toa second embodiment of the present invention;

FIGS. 5A and 5B are three dimensional views of the side bar assemblyaccording to the second embodiment of the present invention, in a lockedand unlocked position, respectively;

FIGS. 6-9 are three dimensional views of various configurations ofpusher and rocker mechanisms for the slider bar actuator device of thepresent invention;

FIGS. 10-12 are views of various configurations for non-resettablethermal interlocks for the actuator device of the present invention;

FIGS. 13-15 are view of various configurations for resettable thermalinterlocks for the actuator device of the present invention;

FIG. 16 is a perspective view of a cylinder barrel according to thepresent invention, illustrating one possible location for the controllerdevice;

FIG. 17 is a circuit block diagram showing one embodiment of a datacarrying key for use with the present invention;

FIG. 18 is a circuit block diagram showing one embodiment of theelectronics of the lock which controls activation of the shape memoryalloy actuator device; and

FIG. 19 is a partial phantom top view of an alternative embodiment ofthe invention wherein a shape memory alloy actuator device is used inconjunction with a tumbler pin blocking mechanism instead of a side barblocking mechanism.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

With reference to FIG. 1, a first embodiment of the present invention isindicated generally by the reference numeral 10 and includes a cylinderor outer shell 20 having a bore 22 in which is positioned a rotatablebarrel or plug 30. The barrel 30 has an outer surface substantiallycorresponding to the bore 22 of the shell and includes a keyway 34configured to receive a key as is known in the art. The barrel 30includes a plurality of tumbler pin bores which receive tumbler pins(not shown) as is known in the art. The manner in which a properlybitted key (not shown) engages the tumbler pins and positions them at ashear line to permit the barrel 30 to be rotated with respect to theshell 20 is known in the art and thus will not be described in any greatdetail herein. However, it should be noted that the tumbler pins may besimply lifted by the bitting surfaces on the key, or they may be liftedrotatively by a key including skew cut bitting surfaces, such as thatused with a Medeco®-type cylinder lock, such as disclosed in U.S. Pat.No. 4,732,022, incorporated herein by reference in its entirety.

The shell 20 includes a cavity 24 in which is positioned a side bar orfence 60 which cooperates with the barrel 30 to either block or permitrotation of the barrel within the shell. As discussed below, the upperwall of the cavity 24 is formed as a camming surface for moving the sidebar out of the barrel upon rotation of the barrel. As can be seen inFIG. 1, the side bar is received in cavity 24 and its inner edge extendsbeyond the internal surface of shell bore 22 and engages the barrel 30to prevent the barrel from rotating to operate the lock. However, whenthe slider bar 50 is moved to the unblocking position shown in FIG. 3B,the barrel may be rotated to cam side bar 60 out of cavity 24 so as toclear the inner surface of bore 22 and permit rotation of the barrel 30with respect to the shell 20.

As described in the '022 patent, one or more side bar springs (notshown) may be positioned between the inner edge of the side bar 60 andthe barrel. The springs bias the side bar into cavity 24, and the sliderbar 50 blocks the side bar from being cammed and thereby prevents thebarrel from rotating.

FIG. 2 is an exploded view of a side bar assembly according to a firstembodiment of the present invention. The assembly includes side bar 60,and an actuator device including a slider bar 50, a rocker 70, a shapememory alloy wire 80, a pusher 90, and a spring 100.

In one preferred embodiment, the shape memory alloy wire 80 is made ofnitinol. Nitinol is a shape memory alloy material (made of a NiTi alloy)which undergoes a crystalline phase change when heated, causing it tocontract or to expand, depending on whether the material is pre-stressedto be in a compressed state or a stretched state. The phase changeoccurs almost instantaneously at a specific temperature, which can bespecified in commercial grades of nitinol wire. Nitinol wire iscommercially available, for example from Dynalloy, Inc. under the tradename Flexinol.

While the use of nitinol is described hereinafter as the shape memoryalloy material for purposes of illustration of a preferred embodiment ofthe invention, it will be noted that the present invention is notlimited to the use of nitinol, but may be implemented by using any otherappropriately suitable material. Examples of other known shape memoryalloy materials include Cu—Al—Ni, Fe—Mn—Si—Cr—Ni, and Cu50-Zr50. Shapememory alloy materials are also commercially available from Shape MemoryApplications, Inc., Santa Clara, Calif.

As shown in FIG. 3A, the slider bar 50 is normally biased by spring 100in a blocking position with respect to side bar 60, such that the sidebar cannot be cammed out of the cavity 24 in the shell and thuspreventing rotation of the barrel. As shown in FIG. 3B, upon activationof the nitinol wire 80, by passing a predetermined amount of electriccurrent through it, the wire 80 will contract, pulling rocker 70 againstpusher 90, which pushes slider bar 50 against the force of spring 100 toa position over a recess 61 in the side bar 60. As such, the side bar 60may be cammed into the barrel by rotation of the barrel, allowing thelock to be opened.

Preferred specifications for nitinol actuator wire to perform 100,000+cycles are as follows:

maximum strain 4% maximum contraction stress ~25,000 psi biasing stress~5,000 to 10,000 psi transition temperature 60 to 110° C.

It is possible to over stress the wire if it is heated too quickly andis subjected to a high inertial load when it starts to contract. Thewire also can be overstressed if it is prevented from contracting to itsfull strain point while being heated to its transition temperature.Appropriate design considerations can eliminate these possibilities.

The rocker and pusher components provide a lever arm arrangement whichserves to provide the appropriate amount of displacement of the sliderbar in response to the maximum tolerable contraction strain on thelength of nitinol wire available for use in a typical cylinder barrelvolume. Some possible variations on the design of the rocker and pushercomponents are shown in FIGS. 6-9. As shown in FIG. 6, rocker 70 a has agroove for accommodating the nitinol wire 80 (formed into a crimped loopas shown in FIG. 7B). The rocker 70 a abuts against an integral sliderand pusher element. FIG. 7A shows a rocker 70 b having ball-shaped endsfor facilitated motion. FIG. 8 shows a “bent pin” rocker configuration70 c, and FIG. 9 illustrates a “turned groove” rocker configuration 70d, wherein the nitinol wire is crimped to the rocker for more secureoperation.

An alternative embodiment of the side bar assembly according to thepresent invention is shown in FIGS. 4, 5A and 5B. In this embodiment,the nitinol wire actuator 81 is used to pull a transverse slider bar 51in a direction perpendicular to the side bar 60. A slider insulator 52is inserted into an aperture in the slider bar 51 and the nitinol wireis threaded through the insulator 52, as shown in FIGS. 5A-5B. A pluginsulator 53 is attached to the end of the nitinol wire or to the plugitself. A spring 101 is inserted into another aperture in the slider bar51 and serves to maintain slider bar 51 normally biased such that anextension on the side bar 60 (not shown in the view) is located belowrecess 54 in the slider bar 51, as shown in FIG. 5A. When the nitinolwire 81 is actuated, the contraction of the wire forces the slider bar51 down against the force of the spring 101, causing the extension onthe side bar to be aligned with the recess 54 as shown in FIG. 5B,thereby allowing the barrel to be rotated, camming the side bar into thebarrel.

Because the shape memory alloy actuator is activated by heat, if thelock were to be heated externally it may be possible to activate thewire. Accordingly, it is necessary to provide an external heat interlockmechanism to prevent external heating of the lock from improperlyactivating the nitinol wire to operate the lock. FIGS. 10-12 showvarious non-resettable heat interlocks. As shown in FIG. 10A, a lowmelting temperature solder 110 connects the nitinol wire to thecontroller device in the barrel. FIG. 10B shows low melt solder 111provided as a cap on the pusher 90. In the event of external heating,the solder will melt, rendering the actuator mechanism inoperable. FIG.11 shows a nitinol ring interlock 112 which is mounted in or adjacent tothe plug. The nitinol ring 112 is prestressed to have a diameter suchthat a post 63 provided on side bar 60 is normally able to pass into orthrough the ring 112 when the side bar is actuated. However, in theevent that the lock is externally heated, the ring 112 will shrink andwill either clamp around post 63 or block post 63 from entering into thering, thus preventing the side bar 60 from being actuated. FIG. 12 showsa nitinol spring 114 which is prestressed in a contracted state and ismounted adjacent to a notch 64 in a leg of side bar 60. If the lock isexternally heated, the spring 114 will expand into the notch 64, therebypreventing the side bar from being retracted. Ring 112 and spring 114 asshown are single cycle interlocks, in that once triggered they renderthe lock permanently disabled. However, it is possible to configure thering 112 and spring 114 such that they will return to their prestressedstate once they return to room temperature, thereby resetting the lock.

FIGS. 13-15 show resettable heat interlocks using various configurationsof bimetallic strips. As shown in FIGS. 13A-13C, a preloaded bimetallicstrip 115 may be provided adjacent to the side bar, which when heatedwill move to block the side bar, preventing movement. FIG. 13B shows theorientation of the bimetallic strip 115 relative to the side bar 60 atroom temperature (viewed from inside the plug), allowing the side bar tobe retracted (in a direction perpendicular to the drawing surface). FIG.13C shows the orientation of the strip 115 when heated. In thisinstance, the strip 115 will flex upward into the path of the side bar60, preventing it from being retracted (i.e., preventing the side barfrom moving in the perpendicular direction out of the page). The thermalinterlock shown in FIGS. 13A-13C must be externally reset oncetriggered. FIGS. 14 and 15 show automatically resetting bimetallicstrips 116 which act in opposition to the nitinol wire when heatedexternally, also preventing the side bar from being moved. As soon asthe bimetallic strips cool to their ambient temperature, they return totheir normal positions, thus allowing the lock to be reset.

Examples of the electronic control circuitry for actuating the nitinolwire is shown in FIGS. 17 and 18. These diagrams correspond to onepreferred electronic security system control as disclosed in U.S. Pat.No. 5,140,317, also incorporated by reference herein in its entirety.However, any equivalent electronic control circuit may be used withoutdeparting from the invention.

FIG. 17 is a schematic block diagram illustrating the components withinan electronic key housing 104. The components include a microcontrolleror microprocessor 501, an electrically erasable programmable read onlymemory (EEPROM) 502 coupled to the controller 501, an oscillator orclock 503 which provides clock signals for the operation of controller501, and a battery power source 504 which operates the controller 501.The battery 504 may also be used to provide power to the circuitrywithin the lock. However, the lock may be provided with its own batterypower source under appropriate circumstances. The electronic keycomponents further include an electronic switch 505 operated by thecontroller 501 and a power sensing circuit 506.

FIG. 18 is a representative schematic block diagram of electroniccircuitry 208 within the lock. An example of the location of thecircuitry is shown in FIG. 16. This circuitry includes a microprocessor601, an EEPROM 602 coupled to the microprocessor 601, an oscillator orclock 603 for providing operational clock signals to the microprocessor601, a power filter 604, electronic switch 605 and load 606 fortransmission of signals to the key controller 501 via line 607, and anelectronic switch 608 for allowing power to flow from power source 504within the key housing 104 through cable 107 and contacts 103-206through the nitinol wire 80 to ground, to activate the nitinol wire.Alternatively, the power source for the nitinol wire may be a separatebattery located within the lock cylinder or cylinder barrel, or externalto the cylinder.

In operation, the microprocessor 601 within the lock makes adetermination as to whether the key inserted into the keyway isauthorized to operate the lock, based upon a comparison of data receivedfrom the key with data stored in the memory associated with themicroprocessor 601. The data used for comparison may be generatedpseudorandomly by the microprocessor 601 in accordance with a storedalgorithm.

In summary, the invention permits conventional mechanical locks to beretrofitted into electro-mechanical locks. For example, a conventionallock, which includes a plurality of tumbler pins that are both raised toa shear line and rotated to a position to accept the legs of a side barby inserting a properly bitted key into the keyway, can be retrofittedby replacing the barrel with an electromechanical barrel constructedaccording to the invention. The electromechanical barrel includes akeyway with a plurality of tumbler pins and a slider bar, the slider barbeing moved by a nitinol actuator mechanism so as to permit the side barto be retracted and the lock operated. In this manner, a purelymechanical lock, which is subject to the limitations discussed above,may be retrofitted into an electromechanical lock which provides thebenefits associated with utilizing an electronically controlled lockingfeature.

FIG. 19 illustrates an alternative embodiment of the present inventionwherein a shape memory alloy actuator is used in conjunction with atumbler pin blocking mechanism. According to this embodiment, a spinner700 which engages a notch 712 in a tumbler pin 710 is provided in theplug 30. The spinner 700 is biased into the notch 712 by a spring force704. A shape memory alloy actuator 706 is provided to actuate a slider708 which engages a boss 702 on the spinner 700.

In operation, at least one tumbler pin 710 is blocked or locked into the“up” position (i.e., through the shear line) by the spinner 700 beingengaged in the notch 712. Upon insertion of an authorized key andsuccessful transfer of data to the control device, the shape memoryalloy actuator 706 is heated by passing a current therethrough, causingthe actuator to contract. The contraction of the actuator 706 causes itto force the slider 708 against the spinner boss 702 in opposition toand overcoming the spring force 704. This causes the spinner 700 torotate to the position shown in phantom in FIG. 19, disengaging it fromthe tumbler pin 710, and allowing the tumbler pin to fall and seatagainst the bitting of the inserted key. If the key bittings match thetumbler pin codes, the key will be able to rotate the plug and open thelock. When the actuator 706 cools, the spring force 704 will again biasit against the tumbler pin 710, such that as the key is removed from theplug, the pin will be raised by the retreating bitting surface of thekey, causing the notch 712 to align with the spinner 710. As the notch712 lines up with the spinner 710, the spring force 704 causes thespinner to engage the notch and again block the pin in an upwardposition within the plug.

The embodiment of FIG. 19 also includes thermal interlock protection.The ends of the shape memory alloy actuator 706 are anchored to bosses720 extending from notches 722 of rotating pins 716. The pins 716 arebiased by spring forces 718 to keep the actuator 706 taut against theslider. A shape memory alloy thermal interlock actuator 714 is alsoanchored to the bosses 720. The actuator 706 is made of a hightransition temperature, low force wire, while the thermal actuator 714is made of a low transition temperature, high force wire.

In the event that the lock is heated externally, the thermal interlockactuator 714 will contract, pulling in the bosses 720 against the springforces 718 and creating slack in the actuator 706. Subsequent activationof the actuator wire 706 will thus merely absorb the imposed slack,preventing the actuator 706 from exerting enough force to move theslider 708 so as to disengage the spinner 700. The thermal interlock isautomatically resettable, in that as the plug cools, the thermalactuator 714 will stretch back to its normal shape, allowing the springforces 718 to rotate the pins 716 to remove the slack in the actuator706.

Those skilled in the art will recognize the many advantages and greatflexibility provided by the present invention. It should be recognizedthat the preferred embodiments discussed above have been described indetail so as to provide a full and complete disclosure thereof, and areonly exemplary of the many possible variations and applications of theteachings of the present invention.

1. An electromechanical lock cylinder, comprising: an outer shell havinga bore formed therein and a cavity extending from the bore into theshell; a barrel disposed within the bore in the shell and beingrotatable relative thereto; a side bar cooperating between the shell andthe barrel for selectively permitting and blocking rotation of thebarrel with respect to the shell, the side bar having a first portionengaging the barrel and a second portion removably received in thecavity in the shell, the side bar being movable relative to the barreland the shell; a blocking mechanism, located in said barrel,positionable in a blocking position in contact with the side bar, whichposition blocks retraction of the side bar from the cavity in the shell,and thereby prevents rotation of said barrel, and also positionable inan unblocking position relative to the side bar, which permits the sidebar to be retracted from the cavity in the shell to allow the barrel tobe rotated with respect to the shell; an electrically activated drivemechanism cooperating with the blocking mechanism to selectively movethe blocking mechanism from the blocking position to the unblockingposition in which the side bar moves out of the cavity upon rotation ofthe barrel; and control means for activating the electrically activateddrive mechanism in response to an authorized attempt to operate the lockcylinder.